In conventional bicycles and tricycles, the seat is between and above the wheels and the pedals are below the rider. The seat may be raised and lowered to accommodate operators of different leg length. Consequently, a tall rider must raise the seat in order to achieve full extension of the leg, for optimum muscle function. Riding high, the operator must bend forward more to operate the handle bars, and bend the neck at an uncomfortable angle to see ahead. With a higher center of gravity, the system has reduced stability. Furthermore, forceful pushing on the pedal lifts the body off the seat. The back is forced into a bent position that is more fatiguing than when in a conventional chair with backrest.
U.S. Pat. No. 4,618,160 issued Oct. 21, 1986 to McElfresh is exemplary of recumbent cycles in which the operator is partially supine with the legs elevated and the handlebars beneath the seat. Both seat and handles adjust together for spacing from the pedals to accommodate different leg lengths. The steering connections, being adjustable, are quite complex. The feet and legs are directly in the line of vision and the head must be bent forward to see ahead. The blood circulation to the leg muscles has evolved for optimum function when the legs are below the hips.